Try standalone app again

Procfile

@@ -1,3 +1,4 @@
 web: bundle exec puma -C config/puma.rb
+cable: bundle exec puma -p 28080 cable/config.ru
 release: ./bin/rails db:migrate
 

config/cable.ru

@@ -0,0 +1,6 @@
+# cable/config.ru
+require_relative "../config/environment"
+Rails.application.eager_load!
+
+run ActionCable.server
+

config/environments/production.rb

@@ -41,13 +41,8 @@
   config.active_storage.service = :local
 
   # Mount Action Cable outside main process or domain.
-  config.action_cable.mount_path = "/cable"
-  config.action_cable.url = ENV["HEROKU_ENV"] == "staging" ?
-    (
-      "wss://socket.staging.nomadstation.io/"
-    ) : (
-      "wss://socket.nomadstation.io/"
-    )
+  config.action_cable.mount_path = nil
+  config.action_cable.url = ENV.fetch("REDIS_URL")
   # config.action_cable.allowed_request_origins = [ "http://example.com", /http:\/\/example.*/ ]
 
   # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.